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The Master Key to the Problem of Reversible Chemical Hydrogen Storage is 12 kJ (mol H2)-1

revised on 20.11.2019 and posted on 29.11.2019 by Roland Hermann Pawelke

This article outlines a potent theoretical formalism illuminating the boundaries to reversible solid hydrogen storage based on the ideal gas law and classic equilibrium thermodynamics. A global picture of chemical reversible hydrogen sorption is unveiled including a thermodynamic explanation of partial reversibility. This is utilized to elucidate a multitude of issues from metal hydride chemistry: Highlights are why the substitution of a mere 4 mol % Na by K in Ti-doped NaAlH4 raises the reversible storage capacity by 42 % and elaboration of the reaction pathway in (Rb/K)H-doped Mg(NH2)2/2LiH. The findings of this work allow for a change of paradigm towards the understanding of reversible chemical energy storage and provide a hitherto missing tool of ample analytic and predictive power, complementary to experiment.


ESA Contract No. 4000105330/12/NL/CLP and EDA Contract No. A-1341-RT-GP


Email Address of Submitting Author


FOTEC Forschungs- und Technologietransfer GmbH



ORCID For Submitting Author


Declaration of Conflict of Interest

There are no conflicts to declare.

Version Notes

V9: A standardization of terminology in a couple of places and Vm° has been corrected from about real to ideal value.